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Biomedical subjects

T G Hislop

Publications and source records attributed to T G Hislop.

At least 55 records · Page 3Linked to original sources
PubMed1988

Radiation dose and second cancer risk in patients treated for cancer of the cervix.

The risk of cancer associated with a broad range of organ doses was estimated in an international study of women with cervical cancer. Among 150,000 patients reported to one of 19 population-based cancer registries or treated in any of 20 oncology clinics, 4188 women with second cancers and 6880 matched controls were selected for detailed study. Radiation doses for selected organs were reconstructed for each patient on the basis of her original radiotherapy records. Very high doses, on the order of several hundred gray, were found to increase the risk of cancers of the bladder [relative risk (RR) = 4.0], rectum (RR = 1.8), vagina (RR = 2.7), and possibly bone (RR = 1.3), uterine corpus (RR = 1.3), cecum (RR = 1.5), and non-Hodgkin's lymphoma (RR = 2.5). For all female genital cancers taken together, a sharp dose-response gradient was observed, reaching fivefold for doses more than 150 Gy. Several gray increased the risk of stomach cancer (RR = 2.1) and leukemia (RR = 2.0). Although cancer of the pancreas was elevated, there was no evidence of a dose-dependent risk. Cancer of the kidney was significantly increased among 15-year survivors. A nonsignificant twofold risk of radiogenic thyroid cancer was observed following an average dose of only 0.11 Gy. Breast cancer was not increased overall, despite an average dose of 0.31 Gy and 953 cases available for evaluation (RR = 0.9); there was, however, a weak suggestion of a dose response among women whose ovaries had been surgically removed. Doses greater than 6 Gy to the ovaries reduced breast cancer risk by 44%. A significant deficit of ovarian cancer was observed within 5 years of radiotherapy; in contrast, a dose response was suggested among 10-year survivors. Radiation was not found to increase the overall risk of cancers of the small intestine, colon, ovary, vulva, connective tissue, breast, Hodgkin's disease, multiple myeloma, or chronic lymphocytic leukemia. For most cancers associated with radiation, risks were highest among long-term survivors and appeared concentrated among women irradiated at relatively younger ages.

Female↗
PubMed1987

Sexual practices, sexually transmitted diseases, and the incidence of anal cancer.

To elucidate the risk factors for anal cancer, we interviewed and obtained blood specimens from 148 persons with anal cancer and from 166 controls with colon cancer in whom these diseases were diagnosed during 1978-1985. We found that in men, a history of receptive anal intercourse (related to homosexual behavior) was strongly associated with the occurrence of anal cancer (relative risk, 33.1; 95 percent confidence interval, 4.0 to 272.1). Anal intercourse was only weakly associated with the risk of anal cancer in women (relative risk, 1.8; 95 percent confidence interval, 0.7 to 4.2). Among the subjects with squamous-cell anal cancer, 47.1 percent of homosexual men, 28.6 percent of heterosexual men, and 28.3 percent of women gave a history of genital warts, as compared with only 1 to 2 percent of controls and no patients with transitional-cell anal cancer. In patients without a history of warts, anal cancer was associated with a history of gonorrhea in heterosexual men (relative risk, 17.2; 95 percent confidence interval, 2.0 to 149.4) and with seropositivity for herpes simplex type 2 (relative risk, 4.1; 95 percent confidence interval, 1.9 to 8.8) and Chlamydia trachomatis (relative risk, 2.3; 95 percent confidence interval, 1.1 to 4.8) in women. Current cigarette smoking was a substantial risk factor in both women (relative risk, 7.7; 95 percent confidence interval, 3.5 to 17.2) and men (relative risk, 9.4; 95 percent confidence interval, 2.3 to 38.5). We conclude that homosexual behavior in men is a risk factor for anal cancer, and that squamous-cell anal cancer is also associated with a history of genital warts, an association suggesting that papillomavirus infection is a cause of anal cancer. Certain other genital infections and cigarette smoking are also associated with anal cancer.

Anus Neoplasms↗
PubMed1987

Patient compliance with screening for fecal occult blood in family practice.

Thirty-two family physicians in British Columbia collaborated in a study to evaluate their patients' compliance when offered testing for fecal occult blood (FOB) with Hemoccult II as a screening test for asymptomatic colorectal cancer. Of the 5003 eligible patients 71% complied. Thirteen variables were investigated. Compliance was found to be directly related to age in a linear manner (chi-squared value for trend = 180.4, p less than 0.0001), age alone correctly classifying 58.5% of the patients as complying or not complying. The association with other variables was less strong. Restricting the consumption of red meat during the test period had no effect on compliance.

Age Factors↗
PubMed1987

The prognostic significance of psychosocial factors in women with breast cancer.

One hundred and thirty three recently diagnosed breast cancer patients completed a self-administered questionnaire which measured 16 psychosocial variables. After 4 years, three variables (expressive activities at home, extroversion, low anger) were significant prognostic factors for overall survival independent of clinical and other psychosocial factors; likewise three variables (expressive activities at home, expressive activities away from home, low cognitive disturbance) were significant independent prognostic factors for disease-free survival. These findings support the prognostic importance of the social emotional network.

Adult↗
PubMed1987

Radiation dose and leukemia risk in patients treated for cancer of the cervix.

To quantify the risk of radiation-induced leukemia and provide further information on the nature of the relationship between dose and response, a case-control study was undertaken in a cohort of over 150,000 women with invasive cancer of the uterine cervix. The cases either were reported to one of 17 population-based cancer registries or were treated in any of 16 oncologic clinics in Canada, Europe, and the United States. Four controls were individually matched to each of 195 cases of leukemia on the basis of age and calendar year when diagnosed with cervical cancer and survival time. Leukemia diagnoses were verified by one hematologist. Radiation dose to active bone marrow was estimated by medical physicists on the basis of the original radiotherapy records of study subjects. The risk of chronic lymphocytic leukemia, one of the few malignancies without evidence for an association with ionizing radiation, was not increased [relative risk (RR) = 1.03; n = 52]. However, for all other forms of leukemia taken together (n = 143), a twofold risk was evident (RR = 2.0; 90% confidence interval = 1.0-4.2). Risk increased with increasing radiation dose until average doses of about 400 rad (4 Gy) were reached and then decreased at higher doses. This pattern is consistent with experimental data for which the down-turn in risk at high doses has been interpreted as due to killing of potentially leukemic cells. The dose-response information was modeled with various RR functions, accounting for the nonhomogeneous distribution of radiation dose during radiotherapy. The local radiation doses to each of 14 bone marrow compartments for each patient were incorporated in the models, and the corresponding risks were summed. A good fit to the observed data was obtained with a linear-exponential function, which included a positive linear induction term and a negative exponential term. The estimate of the excess RR per rad was 0.9%, and the estimated RR at 100 rad (1 Gy) was 1.7. The model proposed in this study of risk proportional to mass exposed and of risk to an individual given by the sum of incremental risks to anatomic sites appears to be applicable to a wide range of dose distributions. Furthermore, the pattern of leukemia incidence associated with different levels of radiation dose is consistent with a model postulating increasing risk with increasing exposure, modified at high doses by increased frequency of cell death, which reduces risk.

Adult↗
PubMed1986

Relationship between risk factors for breast cancer and hormonal status.

A total of 512 breast cancer patients and 540 controls were compared to examine the risk factors for different categories of breast cancer as defined by age, menopausal status and estrogen receptor (ER) tumor status. Significant differences were found by menopausal status, for age at first birth and age at menarche for all women, and for age at first birth and family history for women between 45 and 54 years old. No significant differences were found with ER status alone; however there was a significant difference between ER status and body weight in premenopausal women; the above significant differences with menopausal status were not found when stratified by ER tumour status. These findings support the hypothesis for aetiological differences for pre- and postmenopausal breast cancer and suggest that ER tumour status may influence the risk associated with body weight.

Adult↗
PubMed1986

Study of benign breast disease in a population screened for breast cancer.

We are conducting a study to determine whether risk factors associated with specific pathologic subtypes of benign breast disease (BBD) are similar to those for breast cancer and to evaluate the relationship between clinical and mammographic features of BBD. All women participating in the Canadian National Study of Breast Cancer Screening in Vancouver, B.C., Canada (expected 10,000) are invited to complete a questionnaire designed to gather clinical and epidemiologic information on BBD. Preliminary analysis of the first 736 participants indicates that breast pain and/or tenderness is a significant problem which in its severe from is distressing, anxiety provoking, and adversely affecting quality of life. Breast pain and tenderness is also associated with an increased frequency of clinical signs of BBD and of dense mammographic patterns.

Adult↗
PubMed1986

Childhood and recent eating patterns and risk of breast cancer.

A case-control study was done to examine the relationship between childhood and recent eating practices and risk of breast cancer. Eight hundred forty-six cases and 862 controls returned questionnaires indicating their menopausal status. In premenopausal women, breast cancer risk was increased with recent consumption of foods high in fat content (gravy, beef, pork) and reduced with foods low in fat content (fish); in postmenopausal women, risk was increased with pork consumption only. Regarding carotene sources, risk was reduced with carrot consumption in postmenopausal women only. Similar trends in risk were not found for childhood eating practices. Body weight influenced the breast cancer risk differently for pre- and postmenopausal women: Heavier weight in childhood and teens reduced the risk of premenopausal breast cancer, and heavier weight in adulthood increased the risk of postmenopausal breast cancer. We conclude that fat consumption is associated with breast cancer, especially in premenopausal women.

Adult↗
PubMed1985

Ovarian carcinoma: a multivariate analysis of prognostic factors.

Five hundred and fifty six women with invasive epithelial ovarian carcinoma were assessed for postoperative treatment between 1966 and 1976. The records of this group were reviewed retrospectively. Sixteen characteristics of the patient and tumor were analyzed for prognostic significance by univariate and multivariate techniques. Tumor grade, the presence of residual disease, and patient performance status are identified as stage-specific independent prognostic factors. These independent factors define patient subsets with good, intermediate, and poor prognosis within each stage. The results show that more effective treatment strategies are required for patients in poor prognosis subsets. Estimates of tumor grade, extent of residual disease, and performance status should be included in reports of treatment outcome.

Adult↗
PubMed1984

Breast self-examination: importance of technique in early diagnosis.

Shortly after diagnosis of breast cancer 416 patients were interviewed about their use of screening procedures and the method of tumour detection. Although 72% reported that they performed breast self-examination (BSE), only 12% actually inspected and palpated their breasts monthly. BSE was not significantly associated with tumour size or involvement of the lymph nodes; however, thorough inspection was associated with smaller tumours, and careful palpation with the absence of palpable nodes. Of those who no longer or never had examined their breasts 40% reported having annual breast examinations by their physician and had significantly smaller tumours than did the others. Most of the women (86%) reported having detected their own tumours, and BSE did not significantly increase the likelihood of self-detection. The frequency of use of screening procedures was similar in a sample of women without breast cancer.

Adult↗
PubMed1984

Second primary cancers of the breast: incidence and risk factors.

Between 1946 and 1976 over 9,000 women with breast cancer were seen within one year of diagnosis at the A. Maxwell Evans Clinic (AMEC) in Vancouver, British Columbia. By 1978, 275 had a subsequent diagnosis of a second primary in the contralateral breast: 100 were diagnosed within 1 year, and 175 after 1 year of the first primary. Two separate comparison groups of AMEC patients with unilateral breast cancer were selected to identify risk factors for bilateral breast cancer and to determine the incidence. The average annual incidence rates for a second primary in the contralateral breast were 5.0, 4.1 and 3.0 per 1,000 women for women less than 45 years, 45-54 years, and over 55 years of age at diagnosis of first primary breast cancer, respectively. These rates remained stable for at least 15 years after the diagnosis of the first primary. Two risk factors were found for bilateral cancer within 1 year of the first primary, histologic diagnosis of lobular carcinoma and absence of pathologic involvement of axillary nodes; one risk factor was found for bilateral breast cancer after 1 year of the first primary, family history of breast cancer.

Adult↗
PubMed1984

Oral contraceptives and benign breast disease.

In 1980 a questionnaire was mailed to 726 nurses who had previously entered a study of breast disease in the late 1940s and 1950s; 665 responded. Between the ages of 30 to 49 years, 137 reported detecting their first signs of benign breast disease and 76 reported receiving their first biopsy for these signs. Long-term oral contraceptive usage reduced the risk of developing signs of benign breast disease and the risk of biopsy for these signs. The potential bias due to the effect of prior benign breast disease on the prescribing practices for oral contraceptives was minimized by considering oral contraceptive usage prior to detecting the first signs of benign breast disease.

Adult↗
PubMed1982

Solar radiation in the etiology of cutaneous malignant melanoma in Caucasians.

The evidence for and against a causative association between solar UV radiation and cutaneous malignant melanoma in Caucasians is reviewed. Epidemiological evidence (including descriptive studies of latitude of residence, time and age trends, body site distributions, social class, occupation trends, and case-control studies) and animal experimental data are discussed. On present evidence, solar UV radiation is likely the most important factor in the etiology of cutaneous malignant melanoma in Caucasians, and the effects of UV radiation differ for the various subtypes of melanoma. The needs for further research are also discussed.

Animals↗
PubMed1981

Risk factors for benign breast disease: a 30-year cohort study.

Data on the menstrual history, family history and degree of obesity of 1374 Vancouver nursing students were collected in 1945 and from 1947 to 1956. In 1979, 768 of these women were located; 726 (94%) responded and participated in a follow-up study, providing information on their subsequent medical history and on breast-related problems. No major differences were found between the early histories of these participants and those who were not located or did not respond. Among the respondents 215 gave a history of symptoms compatible with benign breast disease; in 107 this diagnosis was confirmed by biopsy. By age 50 the cumulative risk for benign breast disease was 17% for biopsied and 31% for symptomatic disease. Biopsied benign breast disease was associated with premenstrual breast discomfort, irregular menses, a history of abortions, a family history of both benign and malignant breast disease, lack of use of oral contraceptives, a low index of obesity and small breasts, obesity and breast size being independent. Factors associated with symptomatic benign breast disease were usually associated with a greater likelihood of biopsy for symptomatic disease; hence, the relative risks for biopsied disease were generally greater than those for symptomatic disease. Although the risk factors for benign breast disease differ from those for breast cancer, the findings are consistent with the hypothesis of excessive circulating estrogen.

Abortion, Spontaneous↗
PubMed1981

Conservation of bladder function in patients with invasive bladder cancer treated by definitive irradiation and selective cystectomy.

Four hundred seventy patients with invasive bladder cancer treated by definitive irradiation (5000 rad or more) and selective systectomy were followed to assess their survival status and bladder function status. (90% were followed for at least 10 years or to death.) The survival rates for these patients were similar to those obtained in studies of preoperative irradiation with compulsory systectomy: 5 and 10 year survival rates were 38 and 22% respectively. Sixty-five to 70% of these survivors lived with healthy, functioning bladders to at least 10 years after treatment. Seventy-five had a selective cystectomy, usually for recurrent desease, with an operative mortality rate of 11%. Pre-irradiation catheterization, used to control bladder distension and to reduce the possibility of geopraphic miss in irradiating the tumour, had no effect on the control of local disease or on the long-term survival of patients. Therefore, definitive irradiation with selective cystectomy warrants serious consideration in treating patients with invasive bladder cancer, especially considering the quality of life and the high proportion of patients who retain functioning bladders.

Aged↗